s'il vous plait pouvez m'aider pour mon DM

bonjour,

a = 4/9 - 5/9 = -1/9

b = 7/12 - 36/12 = - 29/12

c = 4/12-3/12 +12/12 = 16/12-3/12 = 13/12

d = 8/5 +2/3 = 24/15 +10/15 = 34/15

e = 4 x 9 /4*3 = 9/3 = 3

f = 5*2 /3*3 x 3*2/ 5*3 =  2/3 x283 = 4/9

g = 2*2 / -3*3 x   -3*5 /2 =  10/3

h = 2/-3 x 3/ 4 = - 2/4 = -1/2

exercice 2

a)
3/5 x 3/4 = 9/20
b)

1500x9/20 = 675